Ubuntu更换阿里源后，提示GPG error缺少公钥

修改命令：sudo gedit /etc/apt/sources.list

阿里源

deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse

错误信息：

W: GPG error: http://mirrors.aliyun.com/ubuntu bionic InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32
E: The repository ‘http://mirrors.aliyun.com/ubuntu bionic InRelease’ is not signed.
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://mirrors.aliyun.com/ubuntu bionic-security InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32
E: The repository ‘http://mirrors.aliyun.com/ubuntu bionic-security InRelease’ is not signed.
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://mirrors.aliyun.com/ubuntu bionic-updates InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32
E: The repository ‘http://mirrors.aliyun.com/ubuntu bionic-updates InRelease’ is not signed.
N: Updating from such a repository can’t be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://mirrors.aliyun.com/ubuntu bionic-proposed InRelease: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32

解决

sudo apt-key adv –keyserver keyserver.ubuntu.com –recv-keys 3B4FE6ACC0B21F32